fixed BUG-31 - ordering multiple series for a book

BUGs

@@ -4,6 +4,3 @@ BUG-7:		if you remove a series from a book, it won't appear in the series drop-d
 
 BUG-30:     failed to add a book with 2 x same author (need to catch error
                 or maybe mess with author list to remove duplicate potentials?)
-
-BUG-31:     series does not have 'series_num', so a book in 2 series, means he ordering is not explicit
-            -> NEED TO display them in order of smallest num_books first

main.py

@@ -138,8 +138,8 @@ class Book(db.Model):
     title = db.Column(db.String(100), unique=True, nullable=False)
     publisher = db.Column(db.Integer, db.ForeignKey('publisher.id'))
     genre = db.relationship('Genre', secondary=Book_Genre_Link.__table__ )
-    loan = db.relationship('Loan', secondary=Book_Loan_Link.__table__);
-    series = db.relationship('Series', secondary=Book_Series_Link.__table__);
+    loan = db.relationship('Loan', secondary=Book_Loan_Link.__table__)
+    series = db.relationship('Series', secondary=Book_Series_Link.__table__,order_by=Series.num_books)
     bsl = db.relationship('Book_Series_Link', overlaps="series" )
     year_published = db.Column(db.Integer)
     condition = db.Column(db.Integer, db.ForeignKey('condition.id'))